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* [PATCH bpf-next v3] bpftool: Remove BPF_OBJ_NAME_LEN restriction when looking up bpf program by name
@ 2022-08-01 13:24 Manu Bretelle
  2022-08-01 21:01 ` Jiri Olsa
  2022-08-04 21:50 ` patchwork-bot+netdevbpf
  0 siblings, 2 replies; 3+ messages in thread
From: Manu Bretelle @ 2022-08-01 13:24 UTC (permalink / raw)
  To: bpf, andrii, quentin

bpftool was limiting the length of names to BPF_OBJ_NAME_LEN in prog_parse
fds.

Since commit b662000aff84 ("bpftool: Adding support for BTF program names")
we can get the full program name from BTF.

This patch removes the restriction of name length when running `bpftool
prog show name ${name}`.

Test:
Tested against some internal program names that were longer than
`BPF_OBJ_NAME_LEN`, here a redacted example of what was ran to test.

    # previous behaviour
    $ sudo bpftool prog show name some_long_program_name
    Error: can't parse name
    # with the patch
    $ sudo ./bpftool prog show name some_long_program_name
    123456789: tracing  name some_long_program_name  tag taghexa  gpl ....
    ...
    ...
    ...
    # too long
    sudo ./bpftool prog show name $(python3 -c 'print("A"*128)')
    Error: can't parse name
    # not too long but no match
    $ sudo ./bpftool prog show name $(python3 -c 'print("A"*127)')

Signed-off-by: Manu Bretelle <chantr4@gmail.com>

Reviewed-by: Quentin Monnet <quentin@isovalent.com>

---

v1 -> v2:
* Fix commit message to follow patch submission guidelines
* use strncmp instead of strcmp
* reintroduce arg length check against MAX_PROG_FULL_NAME

v2 -> v3:
* Fix alignment with opening parenthesis
---
 tools/bpf/bpftool/common.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
index 067e9ea59e3b..8727765add88 100644
--- a/tools/bpf/bpftool/common.c
+++ b/tools/bpf/bpftool/common.c
@@ -722,6 +722,7 @@ print_all_levels(__maybe_unused enum libbpf_print_level level,
 
 static int prog_fd_by_nametag(void *nametag, int **fds, bool tag)
 {
+	char prog_name[MAX_PROG_FULL_NAME];
 	unsigned int id = 0;
 	int fd, nb_fds = 0;
 	void *tmp;
@@ -754,12 +755,20 @@ static int prog_fd_by_nametag(void *nametag, int **fds, bool tag)
 			goto err_close_fd;
 		}
 
-		if ((tag && memcmp(nametag, info.tag, BPF_TAG_SIZE)) ||
-		    (!tag && strncmp(nametag, info.name, BPF_OBJ_NAME_LEN))) {
+		if (tag && memcmp(nametag, info.tag, BPF_TAG_SIZE)) {
 			close(fd);
 			continue;
 		}
 
+		if (!tag) {
+			get_prog_full_name(&info, fd, prog_name,
+					   sizeof(prog_name));
+			if (strncmp(nametag, prog_name, sizeof(prog_name))) {
+				close(fd);
+				continue;
+			}
+		}
+
 		if (nb_fds > 0) {
 			tmp = realloc(*fds, (nb_fds + 1) * sizeof(int));
 			if (!tmp) {
@@ -820,7 +829,7 @@ int prog_parse_fds(int *argc, char ***argv, int **fds)
 		NEXT_ARGP();
 
 		name = **argv;
-		if (strlen(name) > BPF_OBJ_NAME_LEN - 1) {
+		if (strlen(name) > MAX_PROG_FULL_NAME - 1) {
 			p_err("can't parse name");
 			return -1;
 		}
-- 
2.30.2


^ permalink raw reply related	[flat|nested] 3+ messages in thread
* Re: [PATCH bpf-next v3] bpftool: Remove BPF_OBJ_NAME_LEN restriction when looking up bpf program by name
  2022-08-01 13:24 [PATCH bpf-next v3] bpftool: Remove BPF_OBJ_NAME_LEN restriction when looking up bpf program by name Manu Bretelle
@ 2022-08-01 21:01 ` Jiri Olsa
  2022-08-04 21:50 ` patchwork-bot+netdevbpf
  1 sibling, 0 replies; 3+ messages in thread
From: Jiri Olsa @ 2022-08-01 21:01 UTC (permalink / raw)
  To: Manu Bretelle; +Cc: bpf, andrii, quentin

On Mon, Aug 01, 2022 at 06:24:09AM -0700, Manu Bretelle wrote:
> bpftool was limiting the length of names to BPF_OBJ_NAME_LEN in prog_parse
> fds.
> 
> Since commit b662000aff84 ("bpftool: Adding support for BTF program names")
> we can get the full program name from BTF.
> 
> This patch removes the restriction of name length when running `bpftool
> prog show name ${name}`.
> 
> Test:
> Tested against some internal program names that were longer than
> `BPF_OBJ_NAME_LEN`, here a redacted example of what was ran to test.
> 
>     # previous behaviour
>     $ sudo bpftool prog show name some_long_program_name
>     Error: can't parse name
>     # with the patch
>     $ sudo ./bpftool prog show name some_long_program_name
>     123456789: tracing  name some_long_program_name  tag taghexa  gpl ....
>     ...
>     ...
>     ...
>     # too long
>     sudo ./bpftool prog show name $(python3 -c 'print("A"*128)')
>     Error: can't parse name
>     # not too long but no match
>     $ sudo ./bpftool prog show name $(python3 -c 'print("A"*127)')
> 
> Signed-off-by: Manu Bretelle <chantr4@gmail.com>
> 
> Reviewed-by: Quentin Monnet <quentin@isovalent.com>

tested on tetragon programs ;-)

Tested-by: Jiri Olsa <jolsa@kernel.org>

jirka

> 
> ---
> 
> v1 -> v2:
> * Fix commit message to follow patch submission guidelines
> * use strncmp instead of strcmp
> * reintroduce arg length check against MAX_PROG_FULL_NAME
> 
> v2 -> v3:
> * Fix alignment with opening parenthesis
> ---
>  tools/bpf/bpftool/common.c | 15 ++++++++++++---
>  1 file changed, 12 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
> index 067e9ea59e3b..8727765add88 100644
> --- a/tools/bpf/bpftool/common.c
> +++ b/tools/bpf/bpftool/common.c
> @@ -722,6 +722,7 @@ print_all_levels(__maybe_unused enum libbpf_print_level level,
>  
>  static int prog_fd_by_nametag(void *nametag, int **fds, bool tag)
>  {
> +	char prog_name[MAX_PROG_FULL_NAME];
>  	unsigned int id = 0;
>  	int fd, nb_fds = 0;
>  	void *tmp;
> @@ -754,12 +755,20 @@ static int prog_fd_by_nametag(void *nametag, int **fds, bool tag)
>  			goto err_close_fd;
>  		}
>  
> -		if ((tag && memcmp(nametag, info.tag, BPF_TAG_SIZE)) ||
> -		    (!tag && strncmp(nametag, info.name, BPF_OBJ_NAME_LEN))) {
> +		if (tag && memcmp(nametag, info.tag, BPF_TAG_SIZE)) {
>  			close(fd);
>  			continue;
>  		}
>  
> +		if (!tag) {
> +			get_prog_full_name(&info, fd, prog_name,
> +					   sizeof(prog_name));
> +			if (strncmp(nametag, prog_name, sizeof(prog_name))) {
> +				close(fd);
> +				continue;
> +			}
> +		}
> +
>  		if (nb_fds > 0) {
>  			tmp = realloc(*fds, (nb_fds + 1) * sizeof(int));
>  			if (!tmp) {
> @@ -820,7 +829,7 @@ int prog_parse_fds(int *argc, char ***argv, int **fds)
>  		NEXT_ARGP();
>  
>  		name = **argv;
> -		if (strlen(name) > BPF_OBJ_NAME_LEN - 1) {
> +		if (strlen(name) > MAX_PROG_FULL_NAME - 1) {
>  			p_err("can't parse name");
>  			return -1;
>  		}
> -- 
> 2.30.2
> 

^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [PATCH bpf-next v3] bpftool: Remove BPF_OBJ_NAME_LEN restriction when looking up bpf program by name
  2022-08-01 13:24 [PATCH bpf-next v3] bpftool: Remove BPF_OBJ_NAME_LEN restriction when looking up bpf program by name Manu Bretelle
  2022-08-01 21:01 ` Jiri Olsa
@ 2022-08-04 21:50 ` patchwork-bot+netdevbpf
  1 sibling, 0 replies; 3+ messages in thread
From: patchwork-bot+netdevbpf @ 2022-08-04 21:50 UTC (permalink / raw)
  To: Manu Bretelle; +Cc: bpf, andrii, quentin

Hello:

This patch was applied to bpf/bpf-next.git (master)
by Andrii Nakryiko <andrii@kernel.org>:

On Mon,  1 Aug 2022 06:24:09 -0700 you wrote:
> bpftool was limiting the length of names to BPF_OBJ_NAME_LEN in prog_parse
> fds.
> 
> Since commit b662000aff84 ("bpftool: Adding support for BTF program names")
> we can get the full program name from BTF.
> 
> This patch removes the restriction of name length when running `bpftool
> prog show name ${name}`.
> 
> [...]

Here is the summary with links:
  - [bpf-next,v3] bpftool: Remove BPF_OBJ_NAME_LEN restriction when looking up bpf program by name
    https://git.kernel.org/bpf/bpf-next/c/d55dfe587bc0

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html



^ permalink raw reply	[flat|nested] 3+ messages in thread
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2022-08-01 13:24 [PATCH bpf-next v3] bpftool: Remove BPF_OBJ_NAME_LEN restriction when looking up bpf program by name Manu Bretelle
2022-08-01 21:01 ` Jiri Olsa
2022-08-04 21:50 ` patchwork-bot+netdevbpf

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